A Study of Effect of Vanadium on Microstructure and Mechanical Properties of As-Cast and Austempered Ductile Iron

Resumo

The presence of vanadium, as an alloying element, has various effects on the properties of cast irons. In this research, the effects of adding different amounts of vanadium, including 0, 0.87, and 1.45 wt % V, on the microstructure, the formation of different phases, and the mechanical properties of the as-cast and austempered ductile iron have been investigated. After the casting of samples, preparation of the samples, and determining of their chemical composition, it is austenitization heat treatment at 900°C for 45 minutes and austempering heat treatment at 350°C for 60 minutes that were carried out on the samples. Tensile and impact tests, as well as X-ray diffraction (XRD) analysis and metallography, were conducted to study the mechanical properties and the structure. The microstructures of the samples included carbides in the ausferrite matrix. The results show that with increasing the vanadium, tensile strength and impact energy decrease in as-cast ductile iron, whereas heat treatment can improve them.